Seals give information about the validity of a charter and the people involved in a legal act. You can use them to draw conclusions about the significance or immediate circumstances of a document.
Charters with seals from the 15th, 16th, and 18th centuries from the Klosterarchiv Einsiedeln.
Klosterarchiv Einsiedeln, A.BI.33, A.YI.2, A.XI.9.
Charters are often contrasted with narrative sources because they are regarded as direct, physical leftovers of legal processes and not as reflexive descriptions of events. The study of late medieval and modern documents divides archival materials into charters (urkunden) and documents (akten). According to this division, charters secure legal acts, while documents record that legal acts happened.
In general, keep in mind that “a charter is an authenticated and binding piece of writing that was created using specific formulas and that documents an act under the law.” (Hans-Werner Goetz)
The content of a charter can be divided into three parts. In the introduction (protocol), the person in whose name the legal act is done (called the issuer) is named. The main part of the charter (the “text”) contains the legal act and any additional information, like a description of the circumstances or any conditions or clauses to ensure it is carried out. The conclusion (eschatocol) can include a dating formula and any means of authentication that contribute to the legal force of the charter, such as a monogram, seals, and witness lists.
By the later Middle Ages, charters expanded and diversified in function, form, and content. This was especially true for private charters, as more and more often bishops, abbots and abbesses, aristocrats, towns, and councils used documents to record agreements and rulings.